Impedance converter device

ABSTRACT

An improved impedance converter device comprises an electrically conductive external conductor ( 1 ) with one or more connection locations for electrical lines, an electrically conductive internal conductor ( 2 ) with one or more connection locations for electrical lines, and also a dielectric ( 3 ) arranged between external conductor ( 1 ) and internal conductor ( 2 ). The device is distinguished by the following features: 
         the external conductor ( 1 ) comprises a base area ( 1   a ) bounded by one or more side walls ( 1   b,    1   c,    1   d,    1   e ) thereby forming an external conductor housing with an internal space and an opening opposite the base area ( 1   a );    the internal conductor ( 2 ) is arranged in the internal space, the internal conductor ( 2 ) and the external conductor ( 1 ) being insulated from one another by the dielectric ( 3 );    the internal conductor ( 2 ) comprises at least one web-type section ( 2   a,    2   b ) with a web bottom ( 21; 21 ′) and at least one web wall ( 22, 23; 22′, 23 ′) which extends from the web bottom ( 21; 21 ′) in the direction of the opening of the external conductor housing.

The invention relates to an impedance converter device in accordancewith the preamble of Claim 1.

Impedance converters are used nowadays in particular in antennaarrangements for transformation of impedances. The impedance convertersserve for matching the impedances resulting from individual radiatorelements or antenna components, such as e.g. phase shifters, filters,bandpass filters, in broadband fashion to a common system impedance,which is 50 ohms in the field of mobile radio.

The prior art discloses impedance converters in which an impedanceconversion is carried out by means of a λ/4 transformation by virtue ofcoaxial cables having a length corresponding to a quarter of thewavelength of the radio frequency with which the antenna arrangement isoperated being interposed between connections in the antennaarrangement. In this case, it proves to be disadvantageous that, for theinterposition of coaxial cables, a multiplicity of soldering points haveto be provided at the ends of the coaxial cables, so that the productionof such impedance converters is expensive and also greatly affected bytolerances owing to the diversity of parts. Equally, the prior artdiscloses tuning screws for altering the impedance in coaxial elements.This type of impedance conversion is also comparatively expensive.Moreover, impedance transformations are carried out by means ofimpedance converters in the form of strip conductors on circuit boards.What is disadvantageous in this case is that these impedance convertersare permissible only for limited radio-frequency powers and a subsequenttuning of the impedance is not possible; in addition, intermodulationproblems have to be reckoned with.

Therefore, it is an object of the invention to provide an impedanceconverter device which can be produced cost-effectively, is suitable forhigh radio-frequency power and enables a tuning of the impedance in asimple manner.

This object is achieved by means of the independent patent claim.Developments of the invention are defined in the dependent claims.

The impedance converter device according to the invention isdistinguished by a special shaping of an external conductor, of aninternal conductor and also of a dielectric located in between. Theexternal conductor of the device comprises a base area bounded by one ormore side walls, thereby forming an external conductor housing with aninternal space and an opening opposite the base area. The internalconductor is arranged in the internal space, the internal conductor andthe external conductor being insulated from one another by thedielectric. The internal conductor comprises at least one web-typesection with a web bottom and at least one web wall which extends fromthe web bottom in the direction of the opening of the external conductorhousing. The configuration of the external conductor as an open housingenables access to the internal conductor, in particular to the web wallsof the web-type sections. The angle of said web walls can be adjusted bya corresponding tool, thereby enabling an operator to tune the impedancein a simple manner without intermodulation problems occurring or theintermodulation properties being impaired. It should be noted in thiscase that the opening can be closed by a suitable closure device. Whatis crucial, however, is that, on the side opposite the base area, thehousing is not formed in one piece with all the side walls of thehousing, so that an (if appropriate also closed) opening can always belocalized in the impedance converter. A further advantage of theimpedance converter according to the invention is that the externalconductor housing can be used universally and only the readilyaccessible internal conductor has to be exchanged in order to alter thetransformation properties of the impedance converter. On account of thestructural height attained by the external conductor housing,undesirable emissions of the converter do not occur. Moreover, theconverter can be used for very high radio-frequency powers.

Preferably, the impedance converter essentially extends in alongitudinal direction between at least two opposite connectionlocations. Furthermore, at least one web bottom of a web-type internalconductor section is assigned at least two web walls which extend in thedirection of the opening of the external conductor housing in particularfrom edges of the web bottom. In particular, the web walls assigned to aweb bottom are parallel to one another. In one embodiment, the web wallsassigned to a web bottom converge or diverge in the longitudinaldirection of the impedance converter in a sectional view along a planeparallel to the base area of the external conductor. As an alternative,the web walls assigned to a web bottom are parallel to one another.Furthermore, the web walls assigned to a web bottom may be essentiallyperpendicular to the web bottom. As an alternative, the web wallsassigned to a web bottom diverge or converge in the direction of theopening of the external conductor housing in a sectional view along aplane perpendicular to the longitudinal direction of the impedanceconverter.

In a preferred embodiment of the invention, the external conductorcomprises a stamped, one-piece metal sheet with bent-over side walls.This enables the external conductor to be produced extremelyinexpensively since the production by stamping is simple andcost-effective. Analogously, the internal conductor is preferablylikewise a stamped, one-piece metal sheet with bent-over web walls. Thisresults, on the one hand, in cost-effective production of the internalconductor and, on the other hand, ensures good bendability of the webwalls, so that the impedance can easily be tuned or altered by bendingthe web walls.

In a preferred embodiment of the invention, the dielectric is acomponent with a receptacle, the component being inserted in theinternal space of the external conductor housing and the internalconductor being arranged in the receptacle of the component. Thisresults, in a simple manner, in an electrical insulation betweeninternal conductor and external conductor by means of a separatecomponent. In this case, the component is preferably formed in onepiece. Furthermore, in a preferred variant, the component is held byforce locking, in particular by a clamping, and/or by positive lockingand/or by material locking in the external conductor housing.Analogously, the internal conductor may be held by force locking, inparticular by a clamping, and/or by positive locking and/or by materiallocking in the receptacle of the dielectric. This enables simpleassembly of the components of the impedance converter according to theinvention without the need to provide additional fixing means.

In a further preferred variant of the converter, the internal conductorhas, at its ends, end sections with at least one or more end areas whichextend in the direction of the opening of the external conductorhousing. These end sections can be used to fix the position of theinternal conductor in the external conductor housing. When this variantis combined with the embodiment in which the dielectric is a componentwith a receptacle, one or more corners of the receptacle are preferablyrounded and receive edges of the end sections of the internal conductor.

In a particularly preferred embodiment of the invention, the internalconductor has at least one first web-type section for impedancetransformation. In this case, the first web-type section preferably hasa length which is ¼ of the wavelength of a radio frequency which is usedfor mobile radio transmission, in particular a radio frequency in a GSMnetwork and/or UMTS network. In this case, the length is preferablycoordinated with the center frequency to be transmitted. This enablesthe impedance converter according to the invention to be used as a λ/4transformer in customary mobile radio networks. The impedance converteralso makes it possible, if appropriate, to carry out multistage λ/4transformations when using long external conductors.

In a further embodiment of the invention, the internal conductor has atleast one second web-type section for length adaptation of the internalconductor. The second web-type section has the effect that the length ofthe internal conductor is always identical, independently of theradio-frequencies used, so that the internal conductor can always beinserted into an identically constructed external conductor housing.Consequently, the impedance converter can be adapted to differentantenna systems in a simple manner by exchanging the internal conductor.

In order to connect the impedance converter to electrical lines,connection locations are provided in external conductor and in theinternal conductor, said connection locations preferably comprisingopenings at ends of the external conductor and of the internalconductor, respectively. Each opening of the external conductor ispreferably aligned with an opening of the internal conductor, thealigned openings in each case being connected to one another through anopening in the dielectric. The openings of the external conductor and ofthe internal conductor are preferably designed for receiving andsubsequently soldering coaxial cables, the openings of the externalconductor serving to receive a coaxial external conductor and theopenings of the internal conductor serving to receive a coaxial internalconductor. The openings of the dielectric are preferably in each caseaccommodated in cutouts which serve in particular to receive aninsulation arranged between a coaxial external conductor and a coaxialinternal conductor. Furthermore, the openings of the external conductormay comprise at least one shoulder which serves in particular as a stopfor an end of a coaxial external conductor.

In a preferred embodiment of the impedance converter according to theinvention, coaxial cables are soldered by means of soldering pasteand/or integrated soldering moldings at the openings of the externalconductor and of the internal conductor. This enables the coaxial cablesto be soldered to the impedance converter in an automated andcost-effective manner.

In a refinement of the invention, the dielectric used in the impedanceconverter according to the invention may comprise air, which means thatthe internal and external conductors of the impedance converter arespaced apart from one another by additional spacing means.

In a further refinement of the impedance converter according to theinvention, the internal conductor is configured in compartment-likefashion with a plurality of web-type sections arranged parallel. Thisenables the device to be interconnected with a plurality of differentsystems. In order to fix the web-type sections, the latter are in eachcase arranged in a cutout in the dielectric.

Exemplary embodiments of the invention are described below withreference to the accompanying figures, in which:

FIG. 1: shows a perspective view of an impedance converter in accordancewith a first embodiment of the invention;

FIG. 1 a: shows a perspective view of a preferred embodiment of anexternal conductor used in the impedance converter according to theinvention;

FIG. 2: shows a perspective view of the impedance converter of FIG. 1rotated through 180° with respect to FIG. 1;

FIG. 3: shows a plan view of the impedance converter of FIG. 1;

FIG. 4: shows a sectional view of the impedance converter of FIG. 3along the line I-I;

FIG. 5: shows a perspective view of a second embodiment of an impedanceconverter according to the invention;

FIG. 6: shows a perspective view of the impedance converter of FIG. 5rotated through 180° with respect to FIG. 5;

FIG. 7: shows a plan view of the impedance converter of FIG. 6; and

FIG. 8: shows a sectional view of the impedance converter of FIG. 7along the line II-II.

FIG. 1 and FIG. 2 show perspective views of a first embodiment of animpedance converter according to the invention. The converter comprisesan external conductor in the form of an external elongate metal housing1, the housing being open at the top side and comprising a stamped metalsheet. The housing is of essentially rectangular configuration and has abase area 1 a (not visible in FIG. 1 and FIG. 2) and also side walls 1b, 1 c, 1 d and 1 e. As is shown in FIG. 1 a, the external conductor 1is preferably a metal sheet part whose side walls are upwardly bentsections of the metal sheet part. In this case, the edges of theindividual side walls are spaced apart from one another by narrowinterspaces Z. In the interior of the external conductor shown in FIG. 1a, the dielectric 3 may be fixedly clamped by force locking by means ofthe bent side walls.

The dielectric is likewise open at the top side and an internalconductor 2 is inserted in its interior. Said internal conductor has endsections 2 c and 2 d respectively comprising side walls 24, 25, 26 and27, 28, 29. The end sections are pushed into the dielectric 3 by meansof rounded corners 3 a, 3 b, 3 c and 3 d. The internal conductor 2 has alength such that it is fixedly clamped in the internal space of thedielectric 3 by means of the end sections 2 c and 2 d. The internalconductor comprises two web-type sections 2 a and 2 b connected to oneanother between the end sections 2 c and 2 d. The first web-type section2 a comprises a web bottom 21 and two web walls 22 and 23 extendingperpendicularly upward. Analogously, the second web-type section 2 bcomprises a web bottom 21′ (not visible in FIGS. 1 and 2) and web walls22′ and 23′. The internal conductor is preferably formed as a one-piecemetal sheet, in which case, in the metal sheet, first of all the shapingof the side walls of the end section and of the web-type sections isstamped out and then the side walls and web walls are bent upward. Theuse of stamped sheets for the external conductor and the internalconductor ensures inexpensive and simple production of the impedanceconverter.

The transformation impedance can be set by means of the width of theweb-type sections 2 a, 2 b and the corresponding bent-up web walls or bymeans of the height of the web-type sections above the externalconductor bottom (spacing through dielectric).

The first web-type section 2 a serves for impedance transformation ifthe impedance converter is soldered in an antenna arrangement betweencoaxial cables. The length of the first web-type section 2 a is ¼ of awave length λ, as a result of which a λ/4 transformation is carried out,where λ corresponds to the wavelength of the radio frequency with whichthe corresponding antenna arrangement is operated. The customary mobileradio frequencies, such as e.g. 900 or 1800 MHz in GSM networks, arepreferably involved in this case. In contrast to the first web-typesection 2 a, the second web-type section 2 b of the impedance converterprimarily serves for length correction. In other words, the length ofthe second web-type section is always chosen in a manner dependent onthe length of the first web-type section and the total length of theimpedance converter such that the internal conductor is always fixed inthe same position in the dielectric.

The internal conductor 2 has the major advantage that its impedance canbe adapted or altered by bending the web walls of the first web-typesection 2 a. This is advantageous in particular during the manufactureof the impedance converter, since, at the end of the manufacturingprocess, possible tolerances in the impedance can again be compensatedfor by bending the web walls 22 and 23, respectively. If appropriate,the second web-type section may also be configured in such a way that itlikewise influences the impedance, so that the impedance of theconverter can also be altered by bending the web walls 22′ and 23′,respectively.

The external conductor 1 of the impedance converter has a cylindricalopening 101 in the side area 1 e and also two cylindrical openings 102and 103 connected to one another in the side area 1 c. These openingsare connected to smaller cylindrical openings 201, 202 and 203 in theend sections 2 c and 2 d, respectively, via corresponding cylindricalopenings 301, 302 and 303 in the dielectric 3. The openings in theexternal conductor and in the internal conductor serve for connection toa coaxial cable, the openings of the external conductor serving toreceive a coaxial external conductor and the corresponding openings inthe internal conductor serving to receive the corresponding coaxialinternal conductor. In order to fix the coaxial conductors of the cable,the conductors are soldered to the openings. In particular, solderingsfor the coaxial external conductors are provided at the outer sides ofthe side walls 1 c and 1 e of the housing 1 and solderings for thecoaxial internal conductor are provided in the end sections 2 c and 2 dof the internal conductor 2. By means of integrated soldering moldingsor soldering pastes, the internal and external conductor solderingbetween the impedance converter and the coaxial cables can be effectedin an automated manner (e.g. induction soldering). In comparison withconventional impedance converters in which coaxial cables for impedanceconversion are soldered in as an intermediate connection, a smallernumber of soldering locations are required in the impedance converteraccording to the invention. Furthermore, the structural height of theimpedance converter prevents emissions which occur, for example in thecase of impedance converters in the form of strip conductors on circuitboards.

FIG. 3 shows a plan view of the impedance converter from FIG. 1 and FIG.2. FIG. 3 reveals in particular that the web bottom 21 of the firstweb-type section 2 a is wider than the web bottom 21′ of the secondweb-type section 2 b. Furthermore, the length of the second web-typesection is less than the length of the first web-type section. What isachieved by virtue of the size-reduced design of the second web-typesection is that this section has only a small influence or no influenceat all on the impedance of the converter. FIG. 3 furthermore revealsthat the web walls 22 and 23 and also 22′ and 23′ of the web-typesections are readily accessible from above, so that an operator canreadjust or tune the impedance, if appropriate, by bending the webwalls.

FIG. 4 shows a sectional view along the line I-I of FIG. 3, broken linesindicating the position of coaxial cables which are connected to theimpedance converter. Furthermore, the cross section of the externalconductor housing 1 is indicated by a single hatching, whereas the crosssection of the dielectric 3 is represented by a double hatching. FIG. 4reveals, in particular, the diameters of the openings 101 and 103 in theexternal conductor housing, of the openings 301 and 303 in thedielectric and also of the openings 201 and 203 in the internalconductor housing. Of the openings 103, 203 and 303, the opening 103 hasthe largest diameter, and serves to receive a coaxial external conductor51 of a coaxial cable 5. In this case, the inserted coaxial externalconductor stops at a peripheral shoulder S in the opening 103. Theopening 303 has a smaller diameter than the opening 103 and serves toreceive an insulation 53 of the coaxial cable 5. The opening 203 has thesmallest diameter and serves to receive the coaxial internal conductor52 of the coaxial cable 5. The coaxial external conductor 51 is fixed bymeans of a soldering to the outer side of the side wall 1 c.Analogously, the coaxial internal conductor 52 is soldered to the innerside of the side wall 25.

The openings 101, 201 and 301 in the region of the side wall 1 e aredesigned for a larger or lower-attenuation coaxial cable 5′. Analogouslyto the opening 103, the opening 101 has a corresponding shoulder S′against which one end of a coaxial external conductor 51′ stops. Theopening 301 is smaller than the opening 101 and it is arranged in acylindrical cutout A in the dielectric 3, the cutout being chosen insuch a way that the insulation 53′ of the coaxial cable 5′ can beaccommodated therein. The size of the opening 201 in the internalconductor 2 essentially corresponds to the size of the opening 301 inthe dielectric 3, the diameter of the openings being chosen in such away that the coaxial internal conductor 52′ of the coaxial cable 5′ fitsthrough the openings. Analogously to the opposite side of the impedanceconverter, the coaxial internal conductor 52′ is soldered to the innerside of the side wall 28 and the coaxial external conductor 51′ issoldered to the outer side of the side wall 1 e. If, by way of example,two coaxial cables each having an impedance of 50 ohms are inserted viathe openings 102 and 103, an input impedance of 25 ohms is produced atthis location. The impedance of the impedance converter is to be set to35 ohms in such a case, in order that an impedance of 50 ohms isproduced again at the opposite opening 101. Instead of two connectionlocations for coaxial cables at the side wall 1 e, it would also bepossible, if appropriate, to provide only a single connection locationfor an individual coaxial cable.

FIGS. 5 and 6 show two perspective views of a second embodiment of animpedance converter, the view of FIG. 6 being rotated through 180° withrespect to the view of FIG. 5. In contrast to the first embodiment, theinternal conductor 2 of the impedance converter is configured incompartment-type fashion, three web-type sections 2 a, 2 a′ and 2 a″arranged parallel to one another being provided instead of an individualfirst web-type section. However, it is also possible to provide only twoor else more of such web-type sections arranged parallel. The web-typesections are connected to the second web-type section 2 b via atransversely running web 2 e. In order to contact-connect the threefirst web-type sections to corresponding coaxial cables, respectivelyinterconnected openings 102, 103 and 102′, 103′ and 102″, 103″ areprovided in the external conductor 1. Furthermore, each web-type section2 a, 2 a′ and 2 a″ opens into separate end sections 2 c, 2 c′ and 2 c″,respectively, as emerges in particular from FIG. 6. An end section 2 dlikewise adjoins one side of the web-type section 2 b. Analogously tothe preceding embodiment, all the openings in the external conductor 1are aligned with corresponding openings in the dielectric and in theinternal conductor. In order to fix the internal conductor in thedielectric, corresponding receptacles for the end sections 2 c, 2 c′, 2c″ and 2 d are provided in the internal space of the dielectric. Saidreceptacles are formed by parallelepipedal projections 31, 32, 33 and 34at the inner sides of the dielectric. The internal conductor is therebyfixed on the dielectric.

FIG. 7 shows a plan view of the impedance converter of FIG. 5 and FIG.6. FIG. 7 reveals, in particular, the structure of the internalconductor. It can be seen that the three parallel web-type sections 2 a,2 a′, 2 a″ are configured identically and have a larger width than theweb-type section 2 b. However, the web-type sections may also havedifferent widths in order to achieve a desired power division. Bybending the web walls of the web-type sections 2 a, 2 a′ and 2 a″, it isagain possible to tune or alter the impedance since the web-typesections 2 a, 2 a′ and 2 a″ essentially perform the function ofimpedance transformation. The narrower web-type section 2 b serves forlength adaptation or, if appropriate, also for impedance transformationof the three individual branches of the internal conductor 2, the lengthof the section always being chosen such that the internal conductor isfixedly clamped in the internal space of the delectric 3 betweenopposite side walls of the dielectric. On account of its fanned-outform, the impedance converter serves for connecting a plurality ofparallel coaxial cables, thereby enabling an interconnection andimpedance transformation of a plurality of antenna systems.

FIG. 8 shows a sectional view along the line II-II of FIG. 7. Thisreveals, in particular, the dimensions of the cylindrical openings inthe impedance converter, corresponding coaxial cables 5 and 5′ beinginserted in the openings for illustration purposes. The construction ofthe converter in accordance with FIG. 8 is essentially identical to theconstruction of the converter of FIG. 4, identical structural partsbeing designated by the same reference symbols. Therefore, a detaileddescription of the construction of FIG. 8 is dispensed with andreference is made in this respect to FIG. 4. The arrangement of theopenings 103, 203 and 303 in the region of the end section 2 c isillustrated on the left-hand side of the impedance converter of FIG. 8,the arrangement of the openings in the corresponding end sections 2 c′and 2 c″ being identical. Analogously to FIG. 4, the opening 103 has ashoulder S for receiving the coaxial external conductor 51. Likewise, ashoulder S′ is provided on the opposite, right-hand side of theconverter in the opening 101 and the opening 301 is arranged in a cutoutA which serves to receive the insulation 53′. As is described withreference to FIG. 4, the external and internal conductors of the coaxialcables are soldered to the external and internal conductors of theimpedance converter.

1. An impedance converter device for converting impedances in antennaarrangements, comprising: an electrically conductive external conductorwith at least one connection location for electrical lines, anelectrically conductive internal conductor with at least one connectionlocation for electrical lines, a dielectric arranged between theexternal conductor and internal conductors, the external conductorcomprising a base area bounded by at least one side wall thereby formingan external conductor housing with an internal space and an openingopposite the base area; the internal conductor being arranged in theinternal space, the internal conductor and the external conductor beinginsulated from one another by the dielectric; the internal conductorcomprising at least one web-type section with a web bottom and at leastone web wall which extends from the web bottom in the direction of theopening of the external conductor housing.
 2. The device according toclaim 1, wherein the opening of the external conductor housing is closedby means of a closure device.
 3. The device according to claim 1,wherein the impedance converter extends in a longitudinal directionbetween at least two opposite connection locations, and at least one webbottom of a web-type section is assigned at least two web walls whichextend in the direction of the opening of the external conductor housingin particular from edges of the web bottom.
 4. The device according toclaim 3, wherein the web walls assigned to a web bottom converge ordiverge in the longitudinal direction of the impedance converter in asectional view along a plane parallel to the base area of the externalconductor.
 5. The device according to claim 3, wherein the web wallsassigned to a web bottom are parallel to one another.
 6. The deviceaccording to claim 2, wherein the web walls assigned to a web bottom areessentially perpendicular to the web bottom.
 7. The device according toclaim 3, wherein the web walls assigned to a web bottom diverge orconverge in the direction of the opening of the external conductorhousing in a sectional view along a plane perpendicular to thelongitudinal direction of the impedance converter.
 8. The deviceaccording to claim 1, wherein the external conductor comprises astamped, one-piece metal sheet with bent-over side walls.
 9. The deviceaccording to claim 1, wherein the internal conductor comprises astamped, one-piece metal sheet with bent-over web walls.
 10. The deviceaccording to claim 1, wherein the dielectric is a component with areceptacle, the component being inserted in the internal space of theexternal conductor housing and the internal conductor being arranged inthe receptacle of the component.
 11. The device according to claim 10,wherein the component is formed in one piece.
 12. The device accordingto claim 10, wherein the component is held by force locking, clamping,and/or by positive locking and/or by material locking in the externalconductor housing.
 13. The device according to claim 10, wherein theinternal conductor is held by force locking, clamping, and/or bypositive locking and/or by material locking in the receptacle of thedielectric.
 14. The device according to claim 1, wherein the internalconductor has, at its ends, end sections with at least one or more endareas which extend in the direction of the opening of the externalconductor housing.
 15. The device according to claim 14, wherein one ormore corners of the receptacle of the dielectric rounded and receiveedges of the end sections of the internal conductor.
 16. The deviceaccording to claim 1, wherein the internal conductor has at least onefirst web-type section for impedance transformation.
 17. The deviceaccording to claim 16, wherein the internal conductor has at least onesecond web-type section for length adaptation of the internal conductor.18. The device according to claim 16, wherein the first web-type sectionhas a length which is ¼ of the wavelength of a radio frequency which isused for mobile radio transmission, in particular a radio frequency in aGSM network and/or UMTS network.
 19. The device according to claim 1,wherein the connection locations of the external conductor and of theinternal conductor comprise openings, at ends of the external conductorand of the internal conductor.
 20. The device according to claim 19,wherein each opening of the external conductor is aligned with anopening of the internal conductor, the aligned openings in each casebeing connected to one another through an opening in the dielectric. 21.The device according to claim 19, wherein the openings of the externalconductor and of the internal conductor are designed for receiving andsubsequently soldering coaxial cables, the openings of the externalconductor serving to receive a coaxial external conductor and theopenings of the internal conductor serving to receive a coaxial internalconductor.
 22. The device according to claim 20, wherein the openings ofthe dielectric are in each case accommodated in cutouts which serve toreceive an insulation arranged between a coaxial external conductor anda coaxial internal conductor.
 23. The device according to claim 19,wherein the openings of the external conductor comprise at least oneshoulder which serves in particular as a stop for an end of a coaxialexternal conductor.
 24. The device according to claim 19, whereincoaxial cables are soldered by means of soldering paste and/orintegrated soldering moldings at the openings of the external conductorand of the internal conductor.
 25. The device according to claim 1,wherein the dielectric is air.
 26. The device according to claim 1,wherein the internal conductor is configured in compartment-like fashionwith a plurality of web-type sections arranged parallel.
 27. The deviceaccording to claim 26, wherein one end of the web-type sections is ineach case arranged in a cutout in the dielectric.